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DiskOnChip life span calculator

Discussion in 'Embedded' started by Karen Regner, Jul 8, 2003.

  1. Karen Regner

    Karen Regner Guest

    Has anyone tried the DiskOnChip life span calculator, or is it just
    a marketing gimmick? I need to upgrade a system to P4 and am trying
    to decide if I should go with DOC or CompactFlash; we've had problems
    with hard drives due to environmental issues. Unfortunately, customer
    insists on using Windows NT or Win2k and I'm not sure either one will
    work with DOC or CompactFlash.
     
    Karen Regner, Jul 8, 2003
    #1
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  2. Karen Regner

    Juan Lauda Guest

    If you use a CF to IDE adaptor then both NT and 2K should work.
     
    Juan Lauda, Jul 8, 2003
    #2
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  3. Karen Regner

    Guest Guest

    The number I have heard tossed arround is "several days";
    significantly less than a week,

    That was for WinXP. I can't imagine any 'non WinCE' variants being
    significantly different.

    SH7
     
    Guest, Jul 8, 2003
    #3
  4. Karen Regner

    mk Guest

    Hello,

    You need to use WinXp Embedded which has features to minimise the footprint
    and the writes to flash disc.
    If your customer insists on NT or 2K then as far as I am aware there is no
    MS support for prolonging the life of flash disc.

    There is a free evaluation kit for XP embedded which allows you to build a
    system with a 100 day lifetime.

    (All this from MS seminars - I have not actually done it !!)


    Michael Kellett
    www.mkesc.co.uk
     
    mk, Jul 9, 2003
    #4
  5. [...]
    OK, nobody else said it, so I will: this looks like you're in serious
    need of an upgrade to Customer XP --- the all-new "know what they're
    talking about" edition.

    :)
     
    Hans-Bernhard Broeker, Jul 9, 2003
    #5
  6. Karen Regner

    Dave Hansen Guest

    Top-posting fixed.

    [...re: using CF on a Win[2k|XP|NT] system ...]
    A basic feature of any OS of this type would let you configure a RAM
    disk and locate the swapfile and any temporary directories there. I
    know it can be done (i.e., have done it) for various flavors of UN*X.
    I can imagine that WinWhatever might not have such a feature, but
    would be somewhat surprised if that were the case.

    Regards,

    -=Dave
     
    Dave Hansen, Jul 9, 2003
    #6
  7. Karen Regner

    rickman Guest

    Perhaps I am missing something, but I thought there was a special file
    system for Flash which included a wear leveling mechanism to prevent
    constant writes to a single file from wearing out the flash drive. Is
    this not included in standard OS, only embedded OS?

    I worked on a system that ran VxWorks and ran for ages using PCMCIA
    flash cards. We could poll each sector and see how much usage it had
    received. In testing we ran a utility to report the worst case usage
    and it indicated the drive would last for several years of continuous
    usage.

    --

    Rick "rickman" Collins


    Ignore the reply address. To email me use the above address with the XY
    removed.

    Arius - A Signal Processing Solutions Company
    Specializing in DSP and FPGA design URL http://www.arius.com
    4 King Ave 301-682-7772 Voice
    Frederick, MD 21701-3110 301-682-7666 FAX
     
    rickman, Jul 9, 2003
    #7
  8. Karen Regner

    rickman Guest

    Maybe you could put some often accesed files on a ram disk, but a swap
    file is not one that would be useful. A swap file is used to hold data
    that has overflowed ram. Putting that in ram would just make the
    problem worse. Better using no swap file at all.

    --

    Rick "rickman" Collins


    Ignore the reply address. To email me use the above address with the XY
    removed.

    Arius - A Signal Processing Solutions Company
    Specializing in DSP and FPGA design URL http://www.arius.com
    4 King Ave 301-682-7772 Voice
    Frederick, MD 21701-3110 301-682-7666 FAX
     
    rickman, Jul 9, 2003
    #8
  9. Karen Regner

    Brett Guest

    I know it doesn't make sense, but some systems work better swap files even
    if they're on a ram drive. I know in the past Windows really hated not
    having swap space even with a significant amount of ram.
     
    Brett, Jul 9, 2003
    #9
  10. I don't know about windows, but Linux can certainly run without a swap
    file. One thing that can reduce CF lifetime drastically in Linux is the
    fact that the filesystem wants to keep the file's *access* times up to
    date, i.e. even if you only read a file (e.g. when executing a binary)
    this causes a physical write access to the device. Fortuntely, this can
    be disabled by using the -noatime option when mounting the filesystem.
    True.


    Rob
     
    Robert Kaiser, Jul 9, 2003
    #10
  11. I cannot speak for Windoze, but creating swap space on a RAM based
    filesystem is NOT useful under Linux. As mentioned before, it just
    makes things worse.

    Wolfgang Denk
     
    Wolfgang Denk, Jul 10, 2003
    #11
  12. No. This is WRONG. A swap file in RAM will NOT improve performance.
    It will be much more efficient to use NO swap at all.


    Wolfgang Denk
     
    Wolfgang Denk, Jul 10, 2003
    #12
  13. Karen Regner

    Brett Guest

    I have run windows without swap on a box that had like 700-something megs a
    loooong time ago. I though, what could go wrong, it has 700mb ram! I was
    wrong.
     
    Brett, Jul 10, 2003
    #13
  14. ....and on the number of power-cycles. It seems some CF cards perform
    wear-levelling only upon power-up.


    Wolfgang Denk
     
    Wolfgang Denk, Jul 10, 2003
    #14
  15. Karen Regner

    Pat Kohli Guest

    Hello,

    Embedded XP can have a large footprint, and push the RAM, and CPU requirements
    up. If there is no need for USB, or hot swap of PCMCIA, Embedded NT might be
    viable. It includes support for DiskOnChip, and one can disable the swap, IIRC.
    M$ does not seem to market the NT product any more, even though it is sold under
    the Microsoft label. It can be obtained from Venturcom, or Avnet, though.
    http://www.vci.com/

    - Pat
     
    Pat Kohli, Jul 11, 2003
    #15
  16. Karen Regner

    jetmarc Guest

    "The casual reader may think that with a sufficient amount of memory, swap
    This brings up another interesting topic: Compressed ram-based swapfile

    A custom swapfile manager could lzh-compress the pages on swapout, and
    thus tradeoff between speed for often-used pages and small footprint
    for less-often-used pages.

    Of course this will be dead slow when the memory system is at its limits,
    similar to a Windows system with 8MB and literally minutes of continous
    HD access.

    However, it would provide an elegant and automatic solution to the problem
    of never-again-used-pages that you brought up!

    Marc
     
    jetmarc, Jul 11, 2003
    #16
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